A chain saw sharpener and its operation are disclosed in U.S. Pat. No. 3,744,349 (Junker). Although useful, the disclosed sharpener is difficult to clean and maintain in that it is not easily disassembled into its various components. This is because the file guide carriage is held in position and adjusted by the use of two adjustment screws that themselves are secured to a guide bar through the use of collars positioned between the guide bar and the carriage. Since the collars are difficult to remove, it is burdensome (and, some would say, frustrating) to disassemble the sharpener in order to remove foreign material such as dirt, sawdust, and wood chips that may have collected in the sharpener and which may hinder operation.
U.S. Pat. No. 4,677,881 (Jorde) discloses an adjustment screw that requires the use of either a retaining ring and thrust washer or a transverse locking pin to hold the screw in position. Retainers of this type make it difficult to remove the adjustment screw and thus disassemble the sharpener.
Because both chain saws and chain saw sharpeners are used in an outdoor environment where they are constantly exposed to dirt and grime, an improved chain saw sharpener which is easy to disassemble and clean would be an important advancement in the art.